Last active
January 7, 2020 15:45
-
-
Save mfoos/f1f953624c6f0a239286d708341f6b06 to your computer and use it in GitHub Desktop.
Accessing private closure in R package
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
# Goal: To have a function that package users can call to set a variable that | |
# will be used to create a closure. The problem with the "problem" code | |
# is that it exposes the created function (private_function) to the user inappropriately. | |
############################ Problem | |
# a function in my package | |
user_calls <- function(string){ | |
private_function <<- function(){ | |
print(string) | |
} | |
} | |
# another function in my package | |
pkg_function <- function(){ | |
private_function() | |
} | |
# user should be able to do | |
user_calls("kittens") | |
pkg_function() | |
# user should not be able to do | |
private_function() | |
############################ Solution | |
envex <- new.env() | |
user_calls <- function(string){ | |
assign("private_function", function(){ print(string) }, envir = envex) | |
} | |
pkg_function <- function(){ | |
envex$private_function() | |
} | |
user_calls("kittens") | |
pkg_function() |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment